Thanks ETFbitcoin, would I be correct in saying if I was to develop a branded clone of Copay that I would also have to make that open source?
What @HCP said is correct, but i've seen few project forget/don't understand this part of MIT license, which is
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
If you're not sure how to do it, check this explanation
https://opensource.stackexchange.com/a/4061P.S. my advice isn't legal advice